This experiment was conducted to determine the effects of corn particle size on the performance and internal organs weight. These experiments with 192 one-day-old Japanese quail were used in a completely randomized design with four treatments, four replicates (12 quail chickens per replicate). The dietary treatments were: 1) contain of corn particle size 0.5 mm, 2) contain of corn particle size 1 mm, 3) contain of corn particle size 1.5 mm and 4) contain of corn particle size 2 mm. During the experiment characteristics of body weight gain, feed intake and feed conversion ratio of Japanese quails were measured. Results showed that at end of experiment that particle size of corn effective on feed intake, body weight gain, feed conversion and visceral organs weight of (liver, heart, gizzard, proventricular and intestine) were not significant.